968 research outputs found
The Mechanism of Employing the Theoretical Approach in Scientific Research
In the field of sociology, researchers require a theoretical approach when conducting scientific
research due to its significant importance in laying the foundation for understanding the studied
phenomenon. Many students and researchers inquire about the most suitable approach that
contributes to providing the research with a conceptual model and intellectual and ideological
frameworks. These frameworks support the researcher in the process of analysis and interpretation of
the research topic, aiming to achieve logical sequence and methodological coherence throughout each
stage of the research. Consequently, this article aims to explore the theoretical approach and its
application in scientific research in the social sciences, relying on the following elements:
1) Concepts and meanings; 2) The relationship between theory and scientific research; 3) Why we
need a theoretical approach in scientific research?; 4) Employing the theoretical approach in scientific
research; 5) How to formulate the theoretical approach in the theoretical aspect
The role of Ministry of agriculture, forestry and water management in olive growing development
U Älanku se iznosi pregled stanja maslinarstva u Hrvatskoj i mjera Å”to ih poduzima Ministarstvo poljoprivrede Å”umarstva i vodnoga gospodarstva.The situation in olive growing in Croatia and the measures taken by the Ministry of Agriculture, Forestry and Water Management are given in the article
Elektronsko mikroskopijsko prouÄavanje ureÄenja ravninaāālanacaā kod visokotemperaturnih supravodiÄa tipa YBCO
Structures of a number of high-Tc superconducting cuprates related to the prototype YBCO compound, were studied by means of high resolution electron microscopy (HREM) and electron diffraction (ED). Commensurate superstructures or incommensurate modulated structures were induced by various metal atom substitutions for Cu in the \u27\u27chain\u27\u27-layer and its ordering. Metal (M) and oxygen (O) atom ordering is confined mainly in the MO1-x-"chain\u27\u27 layers, while the remaining part of the crystal structure, as well as the material\u27s superconducting features, are hardly affected.Strukture nekih supravodljivih kuprata, sliÄnih osnovnom spoju YBCO s visokim Tc, prouÄavane su tehnikom visoko-razluÄujuÄe elektronske mikroskopije i elektronske difrakcije. NaÄeno je da zamjena atoma bakra u ravninama ālanacaā raznim metalnim atomima uzrokuje njihovo ureÄenje i pojavu sumjerljivih nadstruktura ili nesumjerljivo moduliranih struktura. OdgovarajuÄe ureÄenje metalnih (M) i kisikovih (O) atoma ograniÄeno je na MO1āx ravnine ālanacaā bez veÄeg utjecaja kako na ostali dio strukture, tako i na osnovna supravodljiva svojstva
UreÄenje (Ba/Sr)O-dvoslojeva u supravodljivom kupratu RE2(Ba/Sr)2GaCu2O9
Ordering in the (Ba/Sr/Nd)O bi-layers (of "Rock-Salt" type structure) of the RE2(Ba0.65Sr0.20Nd0.15)2GaCu2O9 high-Tc superconducting cuprate was investigated by electron microscopy and diffraction. Besides the average layered structure based on the tetragonal perovskite cell apĆapĆcp and the meandering chain superstructure based on the orthorhombic 4apĆ2apĆcp cell in the GaO-layers, an additional ordering was found in the pairs of (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O layers. We propose a model for ordering of 3Ba and 1Sr cations on a two-dimensional 2apĆ2ap lattice cell in each (Ba/Sr/Nd)O layer. This compositional intra-layer ordering is accompanied by the inter-layer plane stacking disorder. The 4-fold symmetry of the average tetragonal structure is preserved, while the translation parameters in the (a,b) plane are doubled. This local ordering in the RS-type bi-layers hardly affects the symmetry of the basic structure; however, it may act as a source of weak anisotropy in the CuO2-layers.Strukturno ureÄenje (Ba/Sr/Nd)O dvoslojeva u supravodljivom kupratu sastava RE2(Ba/Sr)2GaCu2O9 istraživano je pomoÄu elektronske mikroskopije i difrakcije. Osim prosjeÄne tetragonske strukture na osnovi slojevite perovskitske tetragonske Äelije ap i ap i cp, i nadstrukture meandrirajuÄih lanaca u GaO-ravninama s ortorombskom Äelijom 4ap i 2ap i cp, nadāeno je dodatno ureÄenje u parovima (Ba/Sr/Nd)O-...-(Ba/Sr/Nd)O ravnina. Predložen je model ureÄenja 3Ba i 1Sr kationa unutar 2ap i 2ap dvodimenzijske Äelije u svakoj (Ba/Sr/Nd)O ravnini. Ovo unutar-ravninsko ureÄenje popraÄeno je meÄu-ravninskim neredom u nizu slaganja slojeva. Simetrija 4-reda, koja je svojstvena prosjeÄnoj tetragonskoj strukturi ostaje saÄuvana, uz podvostruÄenje parametara reÅ”etke u j a k bl ravnini. Opaženo ureÄenje unutar (Ba/Sr/Nd)O dvoslojeva ovog supravodljivog kuprata nema jaki utjecaj na simetriju osnovne strukture, ali može biti izvor lokalne anizotropije u CuO2-ravninama
Quasiparticle Dynamics in the Kondo Lattice Model at Half Filling
We study spectral properties of quasiparticles in the Kondo lattice model in
one and two dimensions including the coherent quasiparticle dispersions, their
spectral weights and the full two-quasiparticle spectrum using a cluster
expansion scheme. We investigate the evolution of the quasiparticle band as
antiferromagnetic correlations are enhanced towards the RKKY limit of the
model. In both the 1D and the 2D model we find that a repulsive interaction
between quasiparticles results in a distinct antibound state above the
two-quasiparticle continuum. The repulsive interaction is correlated with the
emerging antiferromagnetic correlations and can therefore be associated with
spin fluctuations. On the square lattice, the antibound state has an extended
s-wave symmetry.Comment: 8 pages, 11 figure
Magnetic anisotropy of spin tetramer system SeCuO studied by torque magnetometry and ESR spectroscopy
We present an experimental study of macroscopic and microscopic magnetic
anisotropy of a spin tetramer system SeCuO using torque magnetometry and
ESR spectroscopy. Large rotation of macroscopic magnetic axes with temperature
observed from torque magnetometry agrees reasonably well with the rotation of
the tensor above ~K. Below 50~K, the
tensor is temperature independent, while macroscopic magnetic axes continue to
rotate. Additionally, the susceptibility anisotropy has a temperature
dependence which cannot be reconciled with the isotropic Heisenberg model of
interactions between spins. ESR linewidth analysis shows that anisotropic
exchange interaction must be present in SeCuO. These findings strongly
support the presence of anisotropic exchange interactions in the Hamiltonian of
the studied system. Below ~K, the system enters a long - range
antiferromagnetically ordered state with easy axis along the
direction. Small but significant rotation of magnetic axes is also observed in
the antiferromagnetically ordered state suggesting strong spin-lattice coupling
in this system.Comment: 14 pages, 13 figure
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